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UNIVERSITY OF CALIFORNIA 

COLLEGE OF AGRICULTURE 

AGRICULTURAL EXPERIMENT STATION 

BERKELEY, CALIFORNIA 

CIRCULAR 312 

March, 1928 

PRINCIPLES GOVERNING THE CHOICE, 

OPERATION AND CARE OF SMALL 

IRRIGATION PUMPING PLANTS 

C. N. JOHNSTONi 



INTRODUCTION 

The development of agriculture in California depends almost 
entirely upon the progress made in irrigation. Many thousands of 
acres in the state would be unavailable for growing the crops giving 
the higher returns, were it not for the water supplied by irrigation 
pumping plants. All of the standard types of pumps are used to 
some extent in irrigation. The four outstanding types now in use for 
irrigation are the centrifugal, the deep well turbine, the screw, and 
the plunger. Air-lift and rotary displacement pumps are found 
occasionally, and serve only small irrigated areas. 



GENERAL DISCUSSION OF PUMPS 

Pumping for irrigation dates back to the beginning of history 
when men or beasts of burden supplied the power that moved water 
by one means or another. Many machines were developed in Egypt 
and India for this purpose long before the age of mechanical power ; 
today some of these are used in modified form in California. With 
the invention of the steam engine and the demands made by coal-mine 
owners for better pumping machinery late in the eighteenth century, 
progress in the mechanical powering of pumps began. Since this 
time the use of mechanical power as applied to pumps has increased 
rapidly. Today in California about one-sixth of the electrical power 



Junior Irrigation Engineer in the Experiment Station. Eesigned July 16, 1926. 



Z UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 

produced in the state is consumed in driving irrigation pumping 
equipment. This does not take into consideration the pumps driven 
by fuel-oil engines. 

Pumping originally consisted of filling some sort of container or 
carrier by immersion in a body of water and then transporting the 
retained water to a higher elevation. Some pumps use this process 
today. Others are not immersed in the source of supply at all but 
are connected with it through a suction pipe only. In these instances 
the operation of the pump creates a reduction of pressure, or partial 
vacuum, within itself, causing the water at the source to be forced 
into the pump by the greater pressure of the air outside. The amount 
of vacuum or reduction in pressure that must be produced in order 
to raise the water to the pump is roughly equal to the pressure that is 
produced by a column of water equal in height to the vertical distance 
between the center of the pump and the surface of the supply water. 
A perfect vacuum is a total lack of pressure, and if such a condition 
is created in a pump, the water will rise from the source a vertical 
distance of about 34 feet, at sea level. This distance decreases as the 
elevation above sea level increases, because the weight of air diminishes 
with increase of elevation. It is not desirable to place an irrigation 
pump more than 15 to 20 feet above the water source, because friction 
in the suction pipe consumes some of the pressure difference created 
by the pump when in operation. 

Every mechanical contrivance wastes a certain amount of power 
within itself in the performance of its task; this is of course true of 
all pumping equipment. The power delivered by pumping equipment 
divided by the power supplied to it gives a ratio which, when 
expressed as a percentage, is known as the efficiency of the plant. In 
other words, the efficiency of a pumping plant is a measure of its 
behavior while in operation. When the efficiency is low, the. pumping 
cost is higher than it should be, because more power is being wasted 
than is necessary. 

Pumps located above the source of water supply must be capable 
of 'drawing' the water to them when they are started empty, or if 
incapable of so doing, both the pumps and the suction lines must be 
filled with water previous to starting; that is, they must be primed. 
This is accomplished by the use of a hand pitcher-pump or equivalent 
power-driven unit, connected to the highest point of the pump case, 
by means of which the air is withdrawn from the pump and suction 
pipe. The discharge valve being closed during this operation, the 
water rises from below and replaces the air as the latter is withdrawn. 



CIRC. 312 J OPERATION OF SMALL IRRIGATION PUMPING PLANTS 3 

Or, the priming may be accomplished by filling the pump and suction 
pipe with water from some available supply, a flap valve being located 
at the bottom of the suction pipe to prevent the loss of the priming 
water. When the first method is used, the discharge valve is opened 
automatically or by hand as soon as the pump is started. If the 
second is used, the flap valve, or foot valve, opens automatically as 
soon as the pressure of water above is relieved. Pumps whose operat- 
ing parts are submerged in the source of supply require no priming. 



CENTRIFUGAL PUMPS 

The types of pumps used in irrigation in California obtain their 
names largely from their method of applying power to the task of 
moving water. Of the chief types used for irrigation, the centrifugal 
was the first produced in this country, having appeared in Boston 
in 1817. It was called the Massachusetts pump and was made very 
crudely. It had as an impeller four straight paddles or vanes, which 
have been replaced in the modern pump by the curved vanes, forming 
smooth passages for the water. Its principle of operation, however, 
was the same as that of the present-day centrifugal pump, the water 
in both cases being forced through openings in the impellers by 
centrifugal action caused by their high speed of rotation. In the 
centrifugal pump, in other words, as the water is thrown out of the 
impeller it creates the partial vacuum necessary to draw in more 
water and thus continue the operation. 

Centrifugal pumps may be obtained to operate against low or 
high lifts, and to discharge almost any desired quantity of water. 
When they have been purchased to fit the operating conditions, they 
show very good efficiencies. Because these pumps are accessible at 
all times and can be inspected and kept in repair, the efficiency may 
be maintained indefinitely unless the impellers are subject to excessive 
wear from abrasive material in the water. 

The cases, or housings, of these pumps are supplied either as solid 
or as split castings (fig. 1). The solid type has a plate bolted on the 
side, which, when taken off, permits the removal of the shaft with the 
impeller on it. The split type opens on the center line of the shaft, 
exposing bearings, shaft, and impeller. In either case, the impellers 
may be of the open or closed type. The former type is more common 
with the single-suction solid-case pumps. Open impellers, as the name 
implies, are simply impeller vanes mounted or cast against one disk 
or hub. Closed impellers have their vanes mounted between two disks. 



4 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 

They provide better guidance for the water than the open type and 
are generally more efficient. 

The suction-pipe connections in these two types differ, as a rule. 
In the solid-case pump, the suction pipe enters the center of one 
side of the case, so that the water passes into the center, or throat, 
of the impeller on one side only. In the split-case pump, the suction 
line is in the same plane as the impeller, at right angles to the shaft, 
and the pump casing is so built as to lead the water around both sides 




Fig. 1. — Typical pumps. (1) Split-shell centrifugal pump opened for inspec- 
tion; (2) single-suction centrifugal pump opened for inspection; (3) deep well 
turbine model with runners and shaft exposed, full-sized bowls and runner 
being shown in front; (4) single screw from deep well pump; (5) rotary dis- 
placement priming pump. (The pump appears just above the number.) 



CIRC. 312] OPERATION OF SMALL IRRIGATION PUMPING PLANTS 5 

of the case into the two throats of the impeller. Double entry of the 
water into the impeller tends to balance the thrust of the water stream 
entering it — a considerable advantage for this type of construction 
not usually obtained in the single-suction pump. Previously the 
solid-case pumps were often made with two suction pipes, accom- 
plishing the same result as the present split-case pump with its 
divided channels within the case. Special thrust bearings are fre- 
quently placed in both types of pumps to take up any unbalanced 
forces on the impellers. 

The losses in efficiency in centrifugal pumps are attributable to 
air leaks, water slippage, and undue churning of the water. The first 
cause may be eliminated through occasional inspection of the packing 
glands and suction-line connections. The second, in so far as possible, 
is taken care of by correct design, all passageways that can permit 
leakage between discharge and inlet of the impellers being made as 
narrow as possible, and in some cases being made extra long by the 
insertion of grooved rings. For this reason, an impeller should not 
be allowed to rub on the side of the case because of the resulting wear, 
which is accompanied by excessive internal leakage. Churning, the 
third cause of low efficiency, is the natural result of operation and 
may be corrected only in part by proper design and correct speed of 
rotation. This last factor is especially important because the cen- 
trifugal pump is designed to operate at a given rotative speed against 
a given lift, and to throw a predetermined quantity of water. When 
the speed is changed, therefore, from that for which it is designed, 
the pump cannot show its best performance. Churning often arises 
where the pumping lift has remained constant and the discharge has 
been increased by raising the speed of rotation of the pump consider- 
ably above the rated number of revolutions per minute. 

As has been previously stated, irrigation pumps not immersed in 
the supply source should be located not more than 15 to 20 feet above 
that source, and for this reason, as the water level recedes, the pumps 
must be lowered or they cease to operate. In most cases when cen- 
trifugal pumps are used to lift water from wells, they must be set 
in pits at the time of installation. These pits are expensive to con- 
struct and are often dangerous. It is desirable to make them as 
small as possible. For these and other reasons, centrifugal pumps 
have been developed with vertical shafts which permit their operation 
from the ground surface. Pumps with long shafts which are often 
used in deep pits, however, are subject to much trouble, and, conse- 
quently have been largely replaced by the deep well turbine and 
other true deep well types. 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



DEEP WELL TURBINE PUMPS 

The turbine pump is a form of the centrifugal, in which the pump 
case contains stationary curved diffusion vanes that lead the water 
away from the impeller to the discharge opening with a minimum of 
turbulance, receiving the water from the impellers at high velocity 
and passing it on with reduced velocity and increased pressure. Deep 
well turbines (fig. 1) have been developed to meet the requirements 
associated with pumping from wells of limited diameter. They are 
built to operate on a vertical shaft with a single unit or bowl, or with 
several mounted in series, one above the other, the stationary curved 
vanes in the case turning the water from the impeller upward to the 
bowl above, or to the discharge column pipe. 

Because this form of pump is limited in size by the well it must 
enter, it is necessary to forfeit part of the good characteristics of 
operation possible in the centrifugal or turbine not so limited, but 
giving an equivalent discharge. For instance, under present practice, 
the deep well turbine may be operated against a head of about 25 feet 
per bowl, or stage, whereas the centrifugal or turbine designed for 
use outside a pit may be capable of operating at triple this head per 
stage. This is the reason for mounting several bowls in a series in a 
deep well turbine when the pumping lift is more than 25 feet. The 
present tendency in design is for higher rotative speeds, resulting 
in higher heads and greater discharge capacities per bowl. The deep 
well turbine is always mounted with the bowls below the surface of 
the standing water in the well, so that it is always ready to operate 
without priming. This distinct advantage is offset, however, by the 
fact that these rapidly rotating parts are buried in the well, and very 
often receive no attention until they fail to operate. Since minor 
adjustments are likely to be needed in any mechanism that rotates 
at high speed, the efficiency of the deep well turbine is often lowered 
because repairs are not made, owing to the inaccessibility of its 
moving parts. 

Considerable difficulty arises from the fact that power for the deep 
well turbine must be transmitted through a long shaft. Manufacturers 
have adopted many expedients for overcoming this difficulty. Some 
pumps have enclosed drive shafts, in which the bearings of bronze 
or other special material are mounted, while others eliminate the 
bearings entirely and provide wooden guides which extend practically 
the whole length of the shaft, to prevent flopping or whipping. Others 



ClRO. 312] OPERATION OF SMALL IRRIGATION PUMPING PLANTS 7 

accomplish the same result by placing rubber guides or bumpers at 
intervals along- the otherwise exposed shaft. These do not require 
oiling (fig. 2). 

The lubrication necessary to these long drive shafts, which are 
mounted on bearings, is accomplished by several means. Some shafts 
are made hollow in order to carry oil to the bearings; others use the 
drive-shaft housing for this purpose. The bottom bearing of the 
deep well turbine is of such great importance that a special line is 




Pump 
co/umn 



Open bearing in 
spider frame screwed 
info pump co/umn 




fnc/osed metu/lic 
bearing joining fyvo 
sections of drive shaft 
bousing 

Drive shaft bousing 



Drive sbofl, no bearings 

■Dpi 'it yyood liner yvitb 
bo/byv core for s-faft 

Metallic bousing for 
liner and drive shaft 



or 




-H 



£bbber beo'W 
bumper 




Metallic spider frame 

screwed into pump 
"column and supporting 



Fig. 2. 



-Various types of shaft-bearing construction for deep well 
turbine pumps. 



sometimes run down outside the pump to effect its lubrication. In 
other instances, the bearing is packed with grease when assembled 
and is repacked only when repairs become necessary. Since all of 
these devices are liable to failure, they should be inspected whenever 
possible. Rapid deterioration of bearings often results from gritty 
materials which are contained in the water being pumped and which 
become mixed with the lubricating oils. 

These turbine pumps may be purchased for either belt or direct 
connection to the power unit for lifting water any desired distance. 
Some installations at present approach lifts of 500 feet. When kept in 
good condition mechanically, they operate with very good efficiency. 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



SCREW-TYPE PUMPS 

The screw-type pump is an application of the principle used by 
Archimedes to move water upward on an inclined plane turning on 
a movable shaft. There are several types of the screw pumps in use 
in irrigation. All involve fundamentally a rapidly rotating- section 
of an inclined plane, although some have several planes on a common 
hub. Their action in water is the same as that of an electric fan in 
air, which slides the air forward from its rotating, inclined vanes 
(fig. 1). Some are used for heads of less than 10 feet, moving large 
quantities of water ; others are used for medium to high lifts in wells. 

The low-lift screw pump falls into two classes, those whose drive 
shafts are horizontal and those whose shafts are vertical. The units 
with horizontal-drive shafts are very large and are used where large 
quantities of water are to be raised a short distance. The low-lift 
screws on vertical shafts are mostly smaller-capacity ditch pumps, 
which lift the water a few feet out of the ditch onto the land. Some 
of these pumps are very crudely made, being merely a screw mounted 
at the lower end of a shaft enclosed by a rectangular housing and 
supported on one bearing placed at the top. Their efficiency is low, 
and were the lift greater they could not be operated at all because 
the cost of power would be too high. Other designs set in carefully 
planned housings and having substantial bearings show very good 
efficiencies, and because of their simplicity, are readily repaired and 
kept in gcod condition. 

The deep-well form of screw pump is a series of low-lift pumps 
so mounted on a single shaft that they operate as a unit. They are 
assembled from sections about 6 feet long. Each section has two 
screws mounted in it with a single bearing which is supported in a 
spider frame between the two screws. The planes of the spider tend 
to keep the water from whirling as it travels upward. A second set 
of vanes is placed above the upper screw in each unit to stop the 
whirling action of the water leaving that screw. When it is desired 
to pump against a head at the surface of the well, a number of screws 
are nested at the bottom of the pump because the total lift per screw 
cannot exceed about 4 feet and should be about 2 x /2 to 3 feet, under 
which conditions this type of pump operates with very good efficiency. 

Screw pumps are subject to the same difficulties as the deep well 
turbines with their long shafts transmitting the power. Since it is 
impossible to line the drive shaft and bearings with screws located 



UlRC. 3 12 J OPERATION OF SMALL IRRIGATION PUMPING PLANTS 9 

along the length of the shaft, the bearings are open to the entry of 
abrasive substances in the water. This disadvantage is balanced by 
the adaptability of these pumps to changing water tables, because 
sections of pump added at the top or removed from the top, as the 
conditions dictate, will enable the pump to follow the water levels. 
In contrast, the turbine requires complete withdrawal for changing 
the bowls whenever a lowered or raised water table necessitates it. 
As in the case of the turbines, the screw pump is liable to be operated 
when repairs should be made. It requires no priming, since the 
operating parts are immersed in the water supply. As a general rule, 
screw pumps will handle more water than deep well turbines of the 
same outside diameter. 



V/////////////////////////////////Z77Z7 /. 



L 



Moving 
piston 



w//W////w//////////////////////mn 




V//////////A 

Discharge 

'////////////A 



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Fig. 3. — Simple plunger pump. 



PLUNGER PUMPS 

The plunger pump may be obtained in many styles, but its use in 
irrigation is limited by the fact that its capacity is relatively small. 
Fundamentally all plunger pumps are pistons sliding in close-fitting 
chambers (fig. 3) with two valves so arranged that one opens when 
the piston creates a partial vacuum in the chamber, the other being 
forced shut. The reverse occurs when the piston creates a pressure 
in the chamber. The suction line connects to the port over the valve 
that opens under vacuum and the discharge line connects to the port 
over the valve opening under pressure from the piston. The many 
designs of plunger pumps, both power and deep-well types, are all 
applications of the fundamental type either for use in wells or for 
service at the surface of the ground. 

Deep well plunger pumps are used in areas where only a 
limited supply of water is available at a considerable depth, supply- 



10 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 

ing water to a limited area per pump. They operate very efficiently 
against any head when new and if moving clear water, but they are 
subject to excessive wear along the close-fitting surfaces if the water 
contains abrasive material. They require constant attention under 
these conditions as they soon cease to function economically after 
wear starts. They do not need to be primed to start pumping if they 
are in good condition. In fact, small plunger pumps are used as 
priming units for centrifugal installations. 



AIR-LIFT PUMPS 

The air-lift pump, as its name implies, uses air to lift or float the 
water from the source of supply. A compressor injects the air, which 
is sent to the bottom of the pump through a line of pipe let down 
vertically into the water. The pipe enters the bottom of the larger 
pump pipe column (fig. 9) . The air carries out with it as it rises to the 
top of the pipe, a certain amount of the water. For correct operation, 
at least two-thirds of the length of the pump must be below the surface 
of the water supply. When the discharge is at some point above the 
ground surface, a still greater portion must be submerged. Even with 
the best of conditions, an air-lift pump has a very low efficiency. Its 
application in irrigation is, therefore, very limited. It should find 
increasing use, however, in the development of wells, since there are 
no moving parts to be injured by abrasion. 

ROTARY DISPLACEMENT PUMPS 

The rotary displacement pump is another device limited somewhat 
in irrigation use by lack of capacity. Though it is made with many 
forms of internal design, all are dependent upon the rotary motion 
of eccentrically shaped or gear-like impellers that turn in the pump 
case in close-running fit. Because of their shape, they mesh to seal 
off part of the water in the case at a certain point in their revolution 
and then, turning further in mesh, eject the water into the discharge 
pipe (fig. 1). As they are capable of creating a considerable partial 
vacuum if they are kept in good condition, they do not need to be 
filled with water to start pumping, provided they are not too far above 
the supply source. They are occasionally used to prime centrifugal 
pumps. Because the action of the pump depends upon the close fit of 
the impellers, the inclusion of abrasive material in the water being 
moved is disastrous to their operation. They require constant atten- 
tion if the water they handle carries such material, this being their 



ClRC-312] OPERATION OF SMALL IRRIGATION PUMPING PLANTS 



11 



chief disadvantage. They show a good efficiency Avhile the running 
parts are tight but drop off rapidly when wear starts. This type of 
pump is not applicable to deep well pumping. 



CURVE SHEETS 

It is the custom of salesmen in speaking of a pump to refer to its 
curve sheet. Such a sheet is very useful because it gives a graphic 
picture of the operation of the pump in question. Figure 4 gives 
curves for one pump at the given speed and the efficiency discharge 
curve of a second at that same speed. To use the curves one proceeds 
in the following manner : 




200 300 400 £00 600 700 

Discharge in gat/ons per minute 

Fig. 4. — Curve sheet for centrifugal or deep well turbine pump; speed 1165 
r.p.m. The solid lines refer to the first pump. The dotted line is the efficiency 
curve for the second pump, which shows an undesirable curve for conditions of 
varying pumping heads. Each curve represents the relationship of two factors; 
e.g., each of the curves labelled "Plant efficiency — Discharge" represents the 
relationship of the efficiency of one of the plants to its discharge. 

First, note that the three solid-line curves are drawn for a pump 
when turning at 1165 revolutions per minute, for which speed it was 
designed and at which speed it operates best, If driven at any other 
speed, this pump will have different sets of curves. Also note that 
the horizontal base line is scaled to read discharge in gallons per 
minute, while the vertical line indicates pumping head, plant effici- 
ency, and horsepower to motor. 

The most important thing shown in the plant-efficiency — discharge 
curve for the first pump is that when the highest point of efficiency 



12 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 

or 60 per cent, is reached at 460 gallons per minute discharge against 
98 feet pumping head, the input horsepower to the motor will be 
18.5 horsepower. If the head pumped against is not at this point, 
the efficiency is lower. The single dotted line indicates the efficiency- 
discharge curve of the second pump. It illustrates a. characteristic 
design, in which a small change in head or discharge will create a large 
change in efficiency, as compared to the first pump whose efficiency 
curve is not so steep. It is evident, therefore, that the second pump 
is less desirable than the first where pumping lifts are likely to vary. 
A prospective pump owner, then, should buy a pump having a flat- 
topped efficiency-discharge curve, if his water levels are liable to vary. 
Where constant lifts are assured, a sharp-pointed efficiency curve is 
not objectionable, if the point of maximum efficiency fits the operating 
conditions. When pumping lifts are sure to increase, the pump should 
be purchased to operate, when first installed, at a point to the right 
of the point of maximum efficiency rather than to the left. The 
operating conditions will then become constantly better for a time 
after installation. 

THE SELECTION OF MACHINERY 

The above description of the different types of irrigation pumps 
has indicated that each type is adapted to some particular condition, 
such as high or low water table, or large or small discharge. There 
are, however, so many makes of pumping plants available that the 
buyer is often at a loss to determine which to select. He should first 
consider his power unit, which will be driven through a belt if a fuel- 
oil engine is selected. Since pumping is a steady load on an engine, 
the latter must be large enough to drive the pump. Unless over 
capacity is allowed, the life of the engine is materially shortened. 
This is particularly true in the case of light-duty engines such as 
those coming from pleasure cars. If an electric drive is to be used, 
the buyer must determine whether it is to be direct or belt connected. 
Though both connections have advantages, the direct insures positive 
speed maintenance and eliminates some loss. The make of pump 
selected should depend upon the service obtainable from the sellers in 
the given area, provided that the products of several reputable manu- 
facturers are represented. 

A standard form of agreement 2 to cover the sale and purchase 
of irrigation pumping equipment has been drafted by a committee 



2 Moses, B. D., and L. S. Wing. Farmers' Purchase agreement for deep well 
pumps. California Agr. Exp. Sta. Bui. 448:1-46. 1928. 



CIRC. 312] OPERATION OF SMALL IRRIGATION PUMPING PLANTS 13 

representing the pump manufacturers, the California Farm Bureau 
Federation, and other organizations. No buyers should fail to' see 
that his sale contract follows the standard form. Since this agree- 
ment is in substance a guarantee of the performance of the plant 
purchased, it affords protection to sellers and manufacturers, as well 
as consumers, throughout the state. Some satisfactory form of written 
agreement as to performance should be given with every purchase of 
a plant. 

WATER SUPPLIES 

As was indicated earlier in this circular, there are two sources 
of water for irrigation, namely, surface and underground waters. 
Underground supplies are located in the gravels and sands laid down 
by the streams of ancient times. They are supplied by percolation 
from the rains and streams of the present day, mainly the latter. 
Many of these streams of years ago sprang from the same hills and 
mountains as those of today. The beds of the present streams, 
therefore, often cut the old gravel and sand deposits on the mountain 
sides and much of the water in the stream sinks into them, to be 
recaptured only by pumping. 

Because these gravels and sand strata are often supplied by waters 
flowing at a high elevation, they are sometimes found in the valley 
floor under sufficient hydraulic pressure to cause the water to flow out 
of the well. Most of them are under some hydraulic pressure, so that 
the water rises part way up the well casing, at least, when the strata 
are encountered. Wells of this type are called artesian wells whether 
they flow or not. Since the water travels slowly through these water 
strata, irrigation pumping often tends to take the water faster than it 
can be supplied. The pressure in the strata is thus reduced and the 
pumping level lowered. When the draft is large, this lowering is 
often felt in every well drawing from the same strata. Unless the 
winter rains and the streams can replenish the supply during slack 
pumping periods, the drop may become permanent. The water table 
may continue to be lowered in heavily pumped areas until pumping 
becomes uneconomical. 

The sinking of wells to develop underground waters has led to the 
production of a special class of machinery. A large soil auger is used 
to bore into the earth. Sometimes a scow or sand bucket is oscillated 
up and down in earth and water in the hole, gathering in a certain 
part of this mixture through a flap valve located at the bottom. Heavy 
drills or rock bits that pound their way downward are used in areas 




va/ve 





Cutting Mn/ves 



a 



D 



f^r> 



,4 Scow or Sbnd pump 

3 duger or boring too/ 

C Pope sochef 

D Pope sockef sub 

£ Uars or /iommers 

F Scow or fbmp *?ub 

O Pock bif 





Fig. 5. — Types of well-drilling tools used in California. 



ClKC. 312J OPERATION OF SMALL IRRIGATION PUMPING PLANTS 



15 



where rock or boulders are encountered, the loosened material being 
brought to the surface with a sand bucket. Heavy drilling is further 
aided by the use of massive jars or hammers, which give an additional 
blow upon the bit or scow (fig. 5). These tools are operated by well 




^m 



Fig. 6. — Typical well rig used for heavy drilling. Note scow being dumped. 

rigs, consisting of a portable power plant with a tower at one end 
(fig. 6), over which a cable is run for the operation of the scow or 
similar tools, and for the withdrawal of the auger-type tools. The 
augers are actuated by a turn table, powered through a chain or belt 



16 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 

drive from the well rig. The hole made by the drilling tool is gener- 
ally lined with metallic casing forced down as rapidly as space is 
provided for it below. 

Casing is usually either screw-joint pipe or so-called * stove-pipe' 
casing. Both may be obtained for almost any sized well. Stove-pipe 
casing is made from No. 18 or thicker sheet-iron in 2-foot sections 
which are lapped over each other for half their lengths to form a pipe 
whose surfaces are smooth inside and out, and whose walls are a 
double thickness of the sheet metal used. Variations of these two 
types are in use, but not generally in California. One of these, a 
single-riveted casing, is used to some extent in the smaller wells. It 
is made of a single thickness of fairly light sheet-iron. 

While the well is being drilled, a record must be kept of the 
position of the water-bearing strata encountered, in order that the 
casing may be perforated in these areas. Perforating is done by the 
well rig, unless manufactured perforated casing has been obtained 
for direct insertion into the well while drilling is in progress. Many 
contrivances have been used to perforate casing, including both 
cutting knives and punches, but none have been found entirely satis- 
factory. Some wells are never perforated. These depend upon the 
flow attainable from the bottom opening alone and are called open- 
bottom wells. It is only occasionally, however, that a sufficient supply 
can be obtained from this opening alone. On the other hand, it is 
common to seal the bottoms of wells taking their supply through 
perforations, making them closed-bottom wells. The perforations 
are slits or regular-shaped holes in the walls of the casing and are 
arranged more or less uniformly about the circumference of the well 
opposite the water-bearing strata. Unless sufficient openings are made 
in the casing, the resistance to flow through it will be excessive, and 
the water will be unduly lowered, thereby increasing pumping costs. 

One special form of well consists of a hole large in diameter 
and sunk with a rotating auger or drill, from which water is 
ejected. The water washes the loosened materials from the well. 
Into this hole a casing of smaller diameter is inserted, the outside of 
which is surrounded with coarse clean gravel. This method is used 
to provide a greater area of entrance for the ground-waters, since the 
whole casing may be perforated. The clean gravel cylinder on the 
outside permits easy access to the water. The drilling process, how- 
ever, may puddle the walls of the well, thus defeating the purpose 
somewhat. In some localities where the materials penetrated are 
self-supporting, wells may not require casing. 



CIRC. 312] OPERATION OF SMALL IRRIGATION PUMPING PLANTS 17 

Almost all wells when first completed require developing. That 
is, they must be pumped for a considerable time to draw the fine 
particles of earth away from the water strata into the well and out 
through the discharged stream. After the fine particles have been 
removed from the water strata, the flow usually increases, because the 
water can pass through the strata more readily. The discharged water 
also becomes clear. As has been previously suggested, the air-lift can 
be used very satisfactorily for developing wells because it has no 
moving parts. Deep wells should be developed before the pumping 
equipment is ordered. Such a practice would greatly lengthen the 
life of the equipment. The pumps would then operate at higher 
efficiencies, since they could be purchased to meet known conditions 
of operation, and would not be subjected to the abrasion incident to 
the development of the wells. 



WELL AND PUMP TESTS 

After a well has been developed, it should be tested to determine 
the depth to water when the desired discharge stream is being 
obtained. This is important because these measurements indicate the 
character of the well. If possible, the test pump should be run at 
several different speeds, readings of discharge and depth to water 
being obtained for the well while the pump is operating at each speed. 
In this way, the actual tendency of the well can be determined and 
the pumping lift for any discharge can be estimated. This type of 
data is plotted as a curve (fig. 7) enabling one to know fairly accur- 
ately what the probable conditions of operation will be beyond the 
range of the observed data. 

The curve in figure 7 is typical of nearly all wells in California. 
That is, the water stands in the well at a certain depth ; when pumping 
is in progress, this depth increases as the amount being discharged 
increases. The amount of change in depth, or draw-down, with 
changing discharge is not the same for all wells, but depends upon 
the ease with which the water passes through the water-bearing strata 
and the well perforations. The more easily the water moves into the 
well, the smaller will be the change in water level for any given 
discharge rate. The guesswork usually practiced for determining 
these data cannot possibly fit a pump to a given well accurately. 

It is as important to test the new pumping plant when it is in 
place as it is the developed well. Since there is always a chance for 
a slip in the installation of machinery of any type, it is to the advant- 



18 



UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION 



age of the owner, seller, and power company to test every new pump 
installed. Such a test should cover the following items: discharge, 
pumping lift, power requirement, and, of general interest but not 
entirely necessary, the speed of rotation of the pump and motor. 

Discharge may be obtained as follows: Allow the discharge from 
the pump to fall into an open ditch, across which has been constructed 
a bulkhead with a weir notch, similar to that shown in figure 8. 
Make sure that the ditch is large enough so that the water may 
approach the weir without undue haste or turbulence. Be sure that 



so 

46 






































( 


7/?or 


-acte 


risli 


s C 


jrve 


' of 


a ft 


'ell 












46 

\ M 

^4a 

%3S 

§36 

t 






























o 












































































































































c 
























































































30 


































as 

£6 



































<£W 



£50 



30O 350 400 450 500 

Discharge in Oollons per Minute 



550 



600 



Fig. 7. — Curve resulting from plotting well-test data. 



the weir crest is horizontal and the bulkhead perpendicular to the 
ground. Place a small stake a few feet back from the weir and 
beside one bank of the ditch, with its top just level with the crest of 
the w r eir, as shown in figure 8. A carpenter's level may be used to 
set the stake correctly in relation to the weir crest. A ruler held 
perpendicularly with the zero end resting on the top of the stake will 
indicate the depth of water flowing over the weir. The discharge may 
be determined by inspection of the accompanying weir table (table 1). 
The flow in gallons per minute for weirs of different widths is 
indicated opposite the readings of head in inches, as measured on the 
stake in the wier pond. The flow found in the table corresponding to 
the measured head for the weir used is the discharge for the pump. 



CIRC. 312] OPERATION OF SMALL IRRIGATION PUMPING PLANTS 



19 



The method of measuring the pumping lift varies somewhat with 
different types of pumps, on account of the different uses and mount- 
ings. In the case of such pumps as the centrifugal, whose suction and 
discharge lines are completely accessible, the following methods of 
measurements are followed. A vacuum gage is mounted on the suction 
pipe as near the pump as possible ; if the discharge line extends to 
some distance from the pump, a pressure gage is tapped into it also, 



%W^ bulkhead set 
\\\:^Kjnto d/'fch bank 




Beye/ed edge of 
yve/r up stream 



Fig. 



top or~ stoke /eve/ with ""^ 
cr&st of weir 

8. — Rectangular weir in place. A indicates necessary clearance of 
five or more inches between edges of weir and ditch banks. 



close to the pump. The sum of the readings of these two gages con- 
verted into feet, plus the vertical distance between the centers of the 
gages, gives the pumping lift. If the water is discharged from the 
pump close at hand, the pumping lift becomes suction-gage reading in 
.feet, plus the vertical distance from the suction-gage center to the 
center of the discharge pipe at its highest point. 

In the case of pumps whose suction and discharge lines are inacces- 
sible, the pumping lift may be calculated roughly from pipe-friction 
tables, adding the measured vertical distance between the highest 



TABLE 1 

Discarge Table for Eectangular Weirs 



Head 


Discharge 


in gallons 


per minute for crests of various 


lengths 


inches 


lfoot 


1.5 feet 


2 feet 


3 feet 


4feet 


2% 


131 


197 


264 


399 


534 


2H 


140 


212 


284 


428 


575 


2M 
2% 

2V% 


150 


227 


304 


458 


615 


161 


242 


325 


489 


655 


171 


258 


345 


521 


696 


3 


181 


273 


367 


552 


741 


$ 


192 


290 


388 


588 


785 


203 


306 


410 


619 


830 


3^ 


214 


323 


433 


655 


875 


VA 


225 


340 


458 


687 


920 


&A 


237 


357 


480 


723 


969 


m 


248 


375 


503 


759 


1,014 


3»fl« 


260 


393 


530 


794 


1,064 


3^16 


272 


411 


552 


835 


1,113 


4tf 6 


285 


430 


575 


871 


1,167 


4?ie 


297 


448 


601 


907 


1,216 


4#6 


309 


467 


628 


947 


1,266 


4?16 


322 


485 


651 


987 


1,320 


4%6 


334 


507 


678 


1,023 


1,373 


4Hie 


347 


525 


705 


1,064 


1,427 


4^6 


361 


543 


731 


1,104 


1,481 


4^16 


374 


566 


759 


1,145 


1,534 


5Vi 6 


387 


583 


785 


1,189 


1,589 


5?'l6 


401 


606 


812 


1,230 


1,647 


5M 


415 


628 


844 


1,270 


1,706 


5^ 


429 


646 


871 


1,315 


1,764 


5}^ 


443 


669 


898 


1,360 


1,818 


5% 


458 


691 


929 


1,400 


1,876 


5% 


471 


714 


956 


1,445 


1,939 


5Vs 


485 


736 


987 


1,490 


1,997 


6 


498 


754 


1,014 


1,534 


2,056 


6H 


516 


776 


1,046 


1,580 


2,118 


m 


530 


799 


1,077 


1,625 


2,181 


&A 


543 


826 


1,104 


1,674 


2,240 


VA 


561 


848 


1,136 


1,719 


2,303 


m 


575 


871 


1,167 


1,768 


2,365 


QH 


588 


893 


1,198 


1,813 


2,433 


m» 


606 


916 


1,230 


1,863 


2,494 


6»%6 


619 


938 


1,261 


1,912 


2,558 


7H« 


637 


965 


1,293 


1,957 


2,626 


7?'l6 


651 


987 


1,329 


2,006 


2,693 


7%6 


669 


1,010 


1,360 


2,060 


2,756 


7 7 /l6 


682 


1,037 


1,391 


2,105 


2,823 


7?i6 


700 


1,059 


1,423 


2,159 


2,890 


7Hie 


718 


1,086 


1,459 


2,208 


2,958 


71?i6 


732 


1,109 


1,490 


2,258 


3,030 


7»%6 


750 


1,136 


1,526 


2,311 


3,097 


m» 


768 


1,162 


1,557 


2,361 


3,164 


8?i6 


781 


1,185 


1,598 


2,415 


3,236 


8Ji 


799 


1,212 


1,629 


2,464 


3,303 


8^ 


817 


1,239 


1,665 


2,518 


3,375 


8K2 


835 


1,261 


1,697 


2,572 


3,447 


SVs 


853 


1,288 


1,732 


2,626 


3,519 


m 


866 


1,315 


1,768 


2,680 


3,591 


w 


884 


1,342 


1,804 


2,733 


3,667 


9 


902 


1,369 


1,840 


2,787 


3,739 


9M 


920 


1,396 


1,876 


2,841 


3,811 


m 


938 


1,423 


1,912 


2,895 


3,887 


Ws 


956 


1,450 


1,948 


2,953 


3,959 


m 


974 


1,477 


1,984 


3,007 


4,035 


m 


992 


1,504 


2,024 


3,066 


4,111 


m 


1,010 


1,531 


2,060 


3,119 


4,188 


mu 


1,028 


1,557 


2,096 


3,178 


4,264 


9»%a 


1,046 


1,589 


2,132 


3,236 


4,340 


10V.6 


1,064 


1,616 


2,172 


3,290 


4,416 


10^16 


1,082 


1,643 


2,208 


3,348 


4,493 


10%6 


1,104 


1,670 


2,249 


3,407 


4,574 


ioy,6 


1,122 


1,701 


2,289 


3,465 


4,650 


lOfiti 


1,140 


1,728 


2,325 


3,523 


4,731 


ioiy.6 


1,158 


1,759 


2,365 


3,586 


4,807 


101?'l6 


1,176 


1,786 


2,401 


3,645 


4,888 


io'y 16 


1,198 


1,818 


2,442 


3,703 


4,969 


lHie 


1,216 


1,845 


2,482 


3,761 


5,049 


119ia 


1,234 


1,876 


2,522 


3,824 


5,130 


nx 


1,252 


1,903 


2,563 


3,882 


5,211 


n*A 


1,275 


1,934 


2,603 


3,945 


5,292 


n l A 


1,293 


1,961 


2,644 


4,008 


5,377 


n% 


1,315 


1,993 


2,684 


4,066 


5,458 


u% 


1,333 


2,024 


2,724 


4,129 


5,539 


WA 


1,351 


2,051 


2,760 


4,192 


5,624 


12 


1,373 


2,083 


2,805 


4,255 


5,709 



CIRC. 312] OPERATION OF SMALL IRRIGATION PUMPING PLANTS 21 

point of discharge and the supply water surface. Such figures are 
useful only for making a rough check of the operation of a pumping 
plant. 

For pumps such as the deep well turbines installed in such a way 
that their suction lines are inaccessible, but whose discharge lines may 
be tapped, measurement is made of the distance in feet from the ground 
surface to the surface of the supply water. To this is added the vertical 
distance from the ground surface to the center of the discharge pipe at 
its highest point, if the discharge is close to the pump. If it is not, a 
pressure gage must be tapped into the discharge line and its reading 
in feet must be added to the vertical distance in feet between the 
center of the gage and the ground surface, plus the vertical distance 
in feet between the ground surface and the supply- water surface. 
Manufacturers of deep w T ell turbines consider the part of the dis- 
charge column pipe below ground as a portion of the pump, making 
the pumping-lift readings as obtained above acceptable. 

The measurement of the vertical distance between the ground and 
water-supply surface may be obtained only through the use of a 
sounding line (fig. 9). This may be an electrically insulated wire 
with an exposed end let down into the well so that it will ground in 
the water, making a complete circuit with a bell ringer in it. Measure- 
ment of the length of line will give the depth to water. On the other 
hand, it may be an air line of pipe of known length run down into 
the well with the pump. Air is forced into this line and the maximum 
pressure obtainable is recorded in pounds or feet on a gage at the sur- 
face (fig. 9). Some of these gages read the number of feet to water 
direct. Those reading in pounds must be corrected to feet by multi- 
plying the reading by 2.31 (1 pound equals 2.31 cubic feet of water). 
This number of feet indicates the submersion of the end of the air 
line. Subtracting the submersion in feet from the total length of the 
line in feet gives the distance to water. Example : A 120-foot air line 
in a well being pumped requires 13 pounds air pressure to force the 
water out of the line. The pressure goes no higher than 13 pounds, 
because the air escapes at the bottom as fast as more is added when 
this point is reached. Thirteen pounds equals 13 X 2.31 feet of water 
or 30.03 feet of water (call it 30 feet), the submersion of the end of 
the air line. Therefore, the depth to water is 120 feet less 30 feet, or 
90 feet. A direct reading pressure gage scaled in feet would have 
indicated 90 feet immediately under these conditions. All pump 
installations should be designed to permit measurements of the depth 
of water. Special precautions must be taken to make this possible in 
placing deep well pumps. 



Ground wire 
to purnpy 



Telephone 
mogneto 




Air sounding 
line @" pipe) 



Pumping 
yvoter /'eye I 

L 

"Sore end 
on //he 



ferfbrvted 
** cosing 



Fig. 9. — Diagram 
of air-lift pump in 
well, showing two 
methods of sound- 
ing depths in wells. 



\4/r iine from compressor 
enters pump column 
of bottom. 



ClEG. 312] OPERATION OF SMALL IRRIGATION PUMPING PLANTS 



23 



The power input may be measured readily in the field only for 
electrically driven units. Although the power companies will be glad 
to assist in this measurement, the owner can determine it for himself 
after ascertaining the number of watts registered by the electric meter 
in his pumping plant for each revolution of the aluminum disk 
(fig. 10). He should be sure that the figure furnished in watts 
includes any special set-up constants for the installation. After this 




WATT HOUR METER 



'Count rero/L/f/ons 
of f/v's cf/^k 

Fig. 10. — Electric-meter indicating disk. In making a pumping-plant 
test, the revolutions of this disk are to be counted. 

figure, commonly known as a disk constant, is obtained, the number 
of revolutions of the aluminum disk should be counted for several 
minutes and the total divided by the exact number of minutes counted. 
This figure should be multiplied by the constant obtained from the 
power company, and the result multiplied by 60 and divided by 746. 
The final figure is the horsepower being supplied to the motor. With 
the completion of this step, the over-all, or plant efficiency, may be 
computed as follows : Multiply the discharge in gallons per minute by 



24 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION 

the weight of a gallon of water (8.33 pounds) and multiply this by 
the distance the water is lifted, in feet. Then divide the result by 
33,000. The result is horsepower represented by water pumped. 

The plant efficiency is the important item to the user, since it tells 
how well the whole unit is working. From the buyer's viewpoint the 
seller should specify the plant efficiency when indicating the char- 
acteristic of operation. The over-all or plant efficiency is the water 
horsepower output divided by the electrical horsepower input, with 
the result multiplied by 100. Checking the speed of an electrically 
driven unit will occasionally demonstrate a faulty motor, but this 
condition is seldom found. Plants not electrically driven may be 
tested to determine the discharge, the head pumped against, and the 
speed of rotation. The last named requires the use of a speed counter, 
which most pump-installation men have in their equipment. If the 
pump is up to the speed specified, it should deliver the quantity of 
water indicated by the seller for the head being pumped against. 

Tests of an irrigation pumping plant should be made occasionally 
throughout its life so that the necessary adjustments may be made 
to maintain a satisfactory efficiency. 



DISCUSSION OF FIELD CONDITIONS 

Operators of irrigation pumping equipment have always felt 
somewhat dissatisfied with the cost of operation and the performance 
of their pumping equipment. In order to determine the sources of 
this dissatisfaction, investigations were conducted in the field during 
parts of 1924, 1925, and 1926. These consisted of field tests of many 
pumping plants, conducted in as thorough a manner as possible. All 
measurements were checked by several readings, which were averaged. 
All gages were checked for accuracy and in several instances electric 
watt-hour meters were tested by the power companies to make certain 
of their accuracy. These instruments were seldom found more than 
1 per cent in error by the company tester. Wherever possible, weirs 
were used in making readings of discharge and when their use was 
impossible, every effort was made to insure accuracy by checking 
several methods against each other. Soundings to water in the wells 
were made, where possible, with an insulated wire which completed 
an electric circuit with a bell ringer in it when contact was made 
with the water. Occasionally, an air line of known length was avail- 
able and sounding was made with it, checking with the electric 
sounder wherever this could be done. Tables 2 and 3 indicate in 



CIRC, 312] OPERATION OF SMALL IRRIGATION PUMPING PLANTS 



25 



general the results of these tests, showing the average operating con- 
ditions for the three types of pumps tested. These figures might vary 
a few points either way, were they for another set of pumping plants, 
but they represent a fair cross-section of the irrigation pumping 
plants supplied by wells. They are probably typical of the whole 
state, since they were taken in a number of areas. 

TABLE 2 

Eesults of Field Tests of Irrigation Pumping Plants 



Type 


Average 
head 


Average 
discharge 


Plant 
efficiency 


Plants 
tested 


Centrifugal 

Deep well turbine 


feet 

49.9 
124.0 
81.6 


gals, per minute 

3,685.5 

958.5 

1,066.5 


per cent 

49.8 
40.5 
44.5 


33 
31 

27 







TABLE 3 

Approximate Characteristics of Air Lift, Plunger, and Eotary 
Displacement Pumps 



Type 


Average 
discharge 


Average 
efficiency 


Air lift 


gallons per minute 

225 

382.5 

225 


per cent 
23 




60 


Rotary displacement 


50-60 



It will be noted in the tables above that the average discharge of 
the centrifugals is considerably higher than for the other two types 
tested. This is due to the inclusion of several 10 and 20-second-foot 
units among the centrifugal-pump tests. These plants were about 
twenty years old, and their efficiencies were still considerably above 
the average for the type. They were much older than any of the 
screw pumps or deep well turbines tested. The centrifugal pumps 
of capacity corresponding to the other two types showed about the 
average efficiency of their type. In many cases the small centrifugals 
fell considerably below the average for the type. Plant efficiencies 
for the three types ranged from 15.2 per cent in several cases to 70 
per cent in one case. 

The discouraging feature of the tests was that so many plants 
should be operating at one-half or less than one-half of the average 
efficiencies for the type. It is apparent that the average efficiencies 



26 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 




Fig. 11. — Typical deep-well pumping plant in house. 



CIRC. 312] OPERATION OF SMALL IRRIGATION PUMPING PLANTS 27 

are not ideal, since they represent conditions of power waste amount- 
ing to over one-half that furnished. Were the lowest efficiencies up 
to the average for that particular type, the owner's power bill would, 
in some cases, be less than half what it is. Such conditions are largely 
chargeable to failure on the part of the owner to keep his equipment 
in good running order. There is little excuse for centrifugals to go 
far below their normal efficiency because they are accessible at all times 
and repairs are simple. The other two types, as has been mentioned, 
are more difficult to inspect and to repair. However, efficiencies as 
low as some of those found indicate that occasional tests will pay for 
themselves by calling forth the necessary repairs. 

The burden of fault does not rest entirely upon the owners of 
these plants showing low efficiencies, because the manufacturing and 
sales agencies have been responsible for some of this trouble. Their 
equipment has not always stood up in service as it should, because 
makeshifts in construction have been employed. Part of these make- 
shifts are the result of efforts on the part of manufacturers to attain 
a low sale price for their products in order to meet competition. 
Such practice is not countenanced by the more reputable manufac- 
turers, but the individual buyers of pumping equipment often mistake 
poorly made machines for bargains. The electric motor or the electric 
distribution system may be responsible for low efficiencies of operation 
in pumping plants, but this is the exception rather than the rule. 
When an operator has become suspicious of his electrical equipment, 
he should first make sure that the fault is not in the pump. 



SUMMARY 

Centrifugal pumps are simple and are easily cared for. They are 
located on ground-surface foundations or in open pits, as a rule. They 
are best fitted to operate where the water supply is readily approach- 
able, as in the case of surface waters or shallow underground supplies. 
When correctly installed, their efficiency should be good. 

Deep well turbine pumps are much like the centrifugals in per- 
formance, but they are not so easily inspected and kept in repair. 
They may be used to pump water from almost any depth, and if 
inspected and repaired occasionally, should show good operating 
efficiency. 

Screw-type pumps lend themselves to a variety of applications 
including both long and short lifts. Its characteristic is its large 
capacity. In the deep well units, it is hampered in its performance 



28 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION 

by the fact that it is not easily inspected. Its efficiency is good if it 
is inspected and repaired occasionally. 

The air-lift pump has as its chief asset its simplicity and lack of 
wearing- parts, thus making it suitable for use in developing wells. 
Its application to irrigation is limited to special conditions because 
of its low efficiency. 

Because they are limited in capacity, the plunger pumps are 
used generally in irrigating comparatively small tracts. There are 
many areas with deep water supplies of limited capacity served 
largely by this type of pump. Plunger pumps are also limited in 
use by the fact that abrasive materials in the water supply soon cut 
them out, destroying their otherwise very good efficiency. 

The rotary displacement pump is very similar to the plunger 
pump in its application to irrigation. It has the same limitations as 
the latter and also it can be used only where there are surface or 
shallow underground waters. 

To be satisfactory, plant efficiencies should not be below 50 per 
cent. A large number of plants in the field operate considerably 
below this figure. Many are doing so because their owners or operators 
have failed to inspect and repair them as they should. Some pumps 
are so poorly made that they cannot maintain nor even attain 50 per 
cent plant efficiency. These units may be eliminated through proper 
selection by the bivyers. 

New plants should be placed only in a developed well and should 
be tested for operating efficiency. Check tests should be made 
throughout the life of all plants. 



STATION PUBLICATIONS AVAILABLE FOR FREE DISTRIBUTION 



BULLETINS 



No. 

253. Irrigation and Soil Conditions in the 
Sierra Nevada Foothills, California. 

262. Citrus Diseases of Florida and Cuba 

Compared with those of California. 

263. Size Grades for Ripe Olives. 

268. Growing and Grafting Olive Seedlings. 

273. Preliminary Report on Kearney Vine- 
yard Experimental Drain, Fresno 
County, California. 

276. The Pomegranate. 

277. Sudan Grass. 

278. Grain Sorghums. 

279. Irrigation of Rice in California. 
283. The Olive Insects of California. 
294. Bean Culture in California. 

304. A Study of the Effects of Freezes on 

Citrus in California. 
810. Plum Pollination. 
312. Mariout Barley. 
813. Pruning Young Deciduous Fruit 

Trees. 
819. Caprifigs and Caprification. 

324. Storage of Perishable Fruit at Freez 

ing Temperatures. 

325. Rice Irrigation Measurements and 

Experiments in Sacramento Valley, 

1914-1919. 
328. Prune Growing in California. 
331. Phylloxera-Resistant Stocks. 
835. Cocoanut Meal as a Feed for Dairy 

Cows and Other Livestock. 
339. The Relative Cost of Making Logs 

from Small and Large Timber. 
840. Control of the Pocket Gopher in 

California. 

343. Cheese Pests and Their Control. 

344. Cold Storage as an Aid to the Mar- 

keting of Plums. 

346. Almond Pollination. 

347. The Control of Red Spiders in Decid 

uous Orchards. 

348. Pruning Young Olive Trees. 

349. A Study of Sidedraft and Tractor 

Hitches. 

350. Agriculture in Cut-over Redwood 

Lands. 

353. Bovine Infectious Abortion. 

354. Results of Rice Experiments in 1922. 

357. A Self-mixing Dusting Machine for 

Applying Dry Insecticides and 
Fungicides. 

358. Black Measles, Water Berries, and 

Related Vine Troubles. 

361. Preliminary Yield Tables for Second 

Growth Redwood. 

362. Dust and the Tractor Engine. 

363. The Pruning of Citrus Trees in Cali- 

fornia. 

364. Fungicidal Dusts for the Control of 

Bunt. 

365. Avocado Culture in California. 

366. Turkish Tobacco Culture, Curing and 

Marketing. 

367. Methods of Harvesting and Irrigation 

in Relation of Mouldy Walnuts. 

368. Bacterial Decomposition of Olives dur- 

ing Pickling. 

369. Comparison of Woods for Butter 

Boxes. 

370. Browning of Yellow Newtown Apples. 

371. The Relative Cost of Yarding Small 

and Large Timber. 

373. Pear Pollination. 

374. A Survey of Orchard Practices in the 

Citrus Industry of Southern Cali- 
fornia. 

375. Results of Rice Experiments at Cor- 

tena, 1923. 

376. Sun-Drying and Dehydration of Wal 

nuts. 

377. The Cold Storage of Pears. 
379. Walnut Culture in California. 



No. 
380. 

382. 

385. 
386. 

387. 
388. 

389. 
390. 

391. 

392. 
393. 
394. 

395. 
396. 

397. 

398. 
399. 



400. 
401. 

402. 
404. 
405. 
406. 
407. 



408. 
409. 



410. 
411. 
412. 

414. 

415. 
416. 

417. 

418. 

419. 

420. 

421. 
422. 

423. 

424. 

425. 
426. 

427. 

428. 

429. 



Growth of Eucalyptus in California 
Plantations. 

Pumping for Drainage in the San 
Joaquin Valley, California. 

Pollination of the Sweet Cherry. 

Pruning Bearing Deciduous Fruit 
Trees. 

Fig Smut. 

The Principles and Practice of Sun- 
drying Fruit. 

Berseem or Egyptian Clover. 

Harvesting and Packing Grapes in 
California. 

Machines for Coating Seed Wheat with 
Copper Carbonate Dust. 

Fruit Juice Concentrates. 

Crop Sequences at Davis. 

Cereal Hay Production in California. 
Feeding Trials with Cereal Hay. 

Bark Diseases of Citrus Trees. 

The Mat Bean (Phaseolus aeon it if o 
lius). 

Manufacture of Roquefort Type Cheese 
from Goat's Milk. 

Orchard Heating in California. 

The Blackberry Mite, the Cause of 
Redberry Disease of the Himalaya 
Blackberry, and its Control. 

The Utilization of Surplus Plums. 

Cost of Work Horses on California 
Farms. 

The Codling Moth in Walnuts. 

The Dehydration of Prunes. 

Citrus Culture in Central California. 

Stationary Spray Plants in California. 

Yield, Stand and Volume Tables for 
White Fir in the California Pine 
Region. 

Alternaria Rot of Lemons. 

The Digestibility of Certain Fruit By- 
products as Determined for Rumi- 
nants. 

Factors Affecting the Quality of Fresh 
Asparagus after it is Harvested. 

Paradichlorobenzene as a Soil Fumi- 
gant. 

A Study of the Relative Values of Cer- 
tain Root Crops and Salmon Oil as 
Sources of Vitamin A for Poultry. 

Planting and Thinning Distances for 
Deciduous Fruit Trees. 

The Tractor on California Farms. 

Culture of the Oriental Persimmon 
in California. 

Poultry Feeding: Principles and 
Practice. 

A Study of Various Rations for 
Finishing Range Calves as Baby 
Beeves. 

Economic Aspects of the Cantaloupe 
Industry. 

Rice and Rice By-products as Feeds 
for Fattening Swine. 

Beef Cattle Feeding Trials, 1921-24. 

Cost of Producing Almonds in Cali- 
fornia ; a Progress Report. 

Apricots (Series on California Crops 
and Prices). 

The Relation of Rate of Maturity to 
Egg Production. 

Apple Growing in California. 

Apple Pollination Studies in Cali- 
fornia. 

The Value of Orange Pulp for Milk 
Production. 

The Relation of Maturity of Cali- 
fornia Plums to Shipping and 
Dessert Quality. 

Economic Status of the Grape Industry. 



No. 
87. 
117. 

127. 
129. 
136. 

144. 

157. 
164. 
166. 
170. 

173. 

178. 
179. 

202. 

203. 
209. 
212. 
215. 
217. 

230. 

231. 
232. 

234. 

238. 
239. 

240. 

241. 

243. 

244. 
245. 
248. 

249. 
250. 

252. 
253. 
254. 

255. 

256. 
257. 
258. 



Alfalfa. 

The Selection and Cost of a Small 

Pumping Plant. 
House Fumigation. 
The Control of Citrus Insects. 
Melilotus indica as a Green-Manure 

Crop for California. 
Oidium or Powdery Mildew of the 

Vine. 
Control of the Pear Scab. 
Small Fruit Culture in California. 
The County Farm Bureau. 
Fertilizing California Soils for the 

1918 Crop. 
The Construction of the Wood-Hoop 

Silo. 
The Packing of Apples in California. 
Factors of Importance in Producing 

Milk of Low Bacterial Count. 
County Organizations for Rural Fire 

Control. 
Peat as a Manure Substitute. 
The Function of the Farm Bureau. 
Salvaging Rain-Damaged Prunes. 
Feeding Dairy Cows in California. 
Methods for Marketing Vegetables in 

California. 
Testing Milk, Cream, and Skim Milk 

for Butterfat. 
The Home Vineyard. 
Harvesting and Handling California 

Cherries for Eastern Shipment. 
Winter Injury to Young Walnut Trees 

during 1921-22. 
The Apricot in California. 
Harvesting and Handling Apricots 

and Plums for Eastern Shipment. 
Harvesting and Handling Pears for 

Eastern Shipment. 
Harvesting and Handling Peaches for 

Eastern Shipment. 
Marmalade Juice and Jelly Juice from 

Citrus Fruits. 
Central Wire Bracing for Fruit Trees. 
Vine Pruning Systems. 
Some Common Errors in Vine Prun- 
ing and Their Remedies. 
Replacing Missing Vines. 
Measurement of Irrigation Water on 

the Farm. 
Supports for Vines. 
Vineyard Plans. 
The Use of Artificial Light to Increase 



CIRCULARS 
No. 
259. 
261. 
262. 
263. 
264. 



Winter Egg Production. 

Leguminous Plants as Organic Fertil- 
izer in California Agriculture. 

The Control of Wild Morning Glory. 

The Small-Seeded Horse Bean. 

Thinning Deciduous Fruits. 



265. 
266. 

267. 

269. 
270. 
272. 

273. 
276. 
277. 

278. 

279. 

281. 



282. 

283. 
284. 
285. 
286. 
287. 
288. 
289. 
290. 
291. 

292. 
293. 
294. 
295. 

296. 

298. 

300. 
301. 
302. 
303. 

304. 
305. 
306. 

307. 
308. 
309. 



Pear By-products. 

Sewing Grain Sacks. 

Cabbage Growing in California. 

Tomato Production in California. 

Preliminary Essentials to Bovine 

Tuberculosis Control. 
Plant Disease and Pest Control. 
Analyzing the Citrus Orchard by 

Means of Simple Tree Records. 
The Tendency of Tractors to Rise in 

Front; Causes and Remedies. 
An Orchard Brush Burner. 
A Farm Septic Tank. 
California Farm Tenancy and Methods 

of Leasing. 
Saving the Gophered Citrus Tree. 
Home Canning. 
Head, Cane, and Cordon Pruning of 

Vines. 
Olive Pickling in Mediterranean Coun- 
tries. 
The Preparation and Refining of Olive 

Oil in Southern Europe. 
The Results of a Survey to Determine 

the Cost of Producing Beef in Cali- 
fornia. 
Prevention of Insect Attack on Stored 

Grain. 
Fertilizing Citrus Trees in California. 
The Almond in California. 
Sweet Potato Production in California. 
Milk Houses for California Dairies. 
Potato Production in California. 
Phylloxera Resistant Vineyards. 
Oak Fungus in Orchard Trees. 
The Tangier Pea. 
Blackhead and Other Causes of Loss 

of Turkeys in California. 
Alkali Soils. 

The Basis of Grape Standardization. 
Propagation of Deciduous Fruits. 
The Growing and Handling of Head 

Lettuce in California. 
Control of the California Ground 

Squirrel. 
The Possibilities and Limitations of 

Cooperative Marketing. 
Coccidiosis of Chickens. 
Buckeye Poisoning of the Honey Bee. 
The Sugar Beet in California. 
A Promising Remedy for Black Measles 

of the Vine. 
Drainage on the Farm. 
Liming the Soil. 
A General Purpose Soil Auger and its 

Use on the Farm. 
American Foulbrood and its Control. 
Cantaloupe Production in California. 
Fruit Tree and Orchard Judging. 



The publications listed above may be had by addressing 

College of Agriculture, 

University of California, 

Berkeley, California. 

12m-3,'28